Free energy calculations along entropic pathways. I. Homogeneous vapor-liquid nucleation for atomic and molecular systems
Free energy calculations along entropic pathways. I. Homogeneous vapor-liquid nucleation for atomic and molecular systems
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DOI：
10.1063/1.4968231
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发表时间：
2016-11-28
影响因子：
4.4
通讯作者：
Delhommelle, Jerome
中科院分区：
文献类型：
--
作者：
Desgranges, Caroline;Delhommelle, Jerome
使用熵S作为反应坐标，我们确定了原子和分子流体从过饱和蒸汽形成液滴的自由能垒。为了这个目的，我们开发的μ VT - S模拟方法，结合了巨正则系综的优点，它允许直接评估的熵，和伞采样方法，这是非常适合于研究一个激活的过程，如成核。将这种方法应用于原子系统，如Ar，使我们能够测试该方法。结果表明，μ VT - S方法给出了正确的依赖于过饱和度的自由能垒的高度和临界液滴的大小，当从经典的成核理论的预测和以前的模拟结果相比。此外，它提供了洞察熵和液滴形成之间的关系，在整个过程中。μ VT-S方法的另一个优点是它可以直接转移到分子系统，因为它使用系统的熵作为反应坐标。本文介绍并讨论了μ VT-S模拟方法在N-2和CO2中的应用，显示了μ VT-S方法的多功能性。出版社：AIP Publishing
Using the entropy S as a reaction coordinate, we determine the free energy barrier associated with the formation of a liquid droplet from a supersaturated vapor for atomic and molecular fluids. For this purpose, we develop the mu VT - S simulation method that combines the advantages of the grandcanonical ensemble, that allows for a direct evaluation of the entropy, and of the umbrella sampling method, that is well suited to the study of an activated process like nucleation. Applying this approach to an atomic system such as Ar allows us to test the method. The results show that the mu VT - S method gives the correct dependence on supersaturation of the height of the free energy barrier and of the size of the critical droplet, when compared to predictions from the classical nucleation theory and to previous simulation results. In addition, it provides insight into the relation between the entropy and droplet formation throughout this process. An additional advantage of the mu VT - S approach is its direct transferability to molecular systems, since it uses the entropy of the system as the reaction coordinate. Applications of the mu VT - S simulation method to N-2 and CO2 are presented and discussed in this work, showing the versatility of the mu VT - S approach. Published by AIP Publishing.